Yes, because Goldeneye made full use of the Xbox's graphical processing capabilities. :rolleyes2

I'm not sure which it would be. Halo 2's cutscenes were fantastic, and the fact that they suffered from some pop-in suggests that the system could barely handle displaying it all. For the best all-around good looking game, though, I imagine Doom 3 was the most demanding. But Half-Life 2 was no slouch either. I'd vote Doom, but just by a hair.